title: Shift of temporal responsivity curve of pattern reversal visually evoked potentials to lower frequencies in patients after recovery from optic neuritis.
abstract: OBJECTIVE
  To investigate the responsivity of the visual system to pattern reversal stimuli of different reversal rates in optic neuritis patients after a full recovery of visual acuity.
  
  
  METHODS
  Thirty eyes with optic neuritis and 30 eyes of age-matched normal controls were studied. Steady-state pattern reversal visually evoked potentials (P-VEPs) were recorded using reversal rates of 2, 10, 20 and 30 Hz. The relationship between the amplitudes of the P-VEPs and reversal rate was analysed. The temporal responsivity curves of the two groups were compared.
  
  
  RESULTS
  The means ± standard deviations (SDs) of the P-VEP amplitudes in the normal controls were 7.08 ± 2.97, 8.60 ± 2.37, 4.69 ± 1.99 and 2.11 ± 1.24 μV at reversal rates of 2, 10, 20 and 30 Hz, respectively. The comparable amplitudes from the recovered optic neuritis patients were 8.01 ± 2.45, 6.57 ± 2.54, 2.73 ± 1.76 and 0.94 ± 1.27 μV. The mean amplitude of the P-VEPs elicited at a reversal rate of 2 Hz was not significantly different from that of normal controls. However, the amplitudes of the P-VEPs at reversal rates of 10, 20 and 30 Hz were significantly smaller in the recovered optic neuritis patients than in the controls. In addition, the average maximum amplitude of the P-VEPs was obtained at 10 Hz in normal subjects and at 2 Hz in the recovered optic neuritis patients.
  
  
  CONCLUSIONS
  These results indicate that the peak of the temporal tuning curve of the P-VEP shifts to lower frequencies in recovered optic neuritis eyes, and that the reduced amplitudes at higher frequencies seem to be characteristic of the visual system of patients with recovered optic neuritis.
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Japan. takashi@poh.osaka-med.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Okuno
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Oku
authors.forename: Jun
authors.initials: J
authors.lastname: Sugasawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Utsumi
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009902:Optic Neuritis / Q000503:physiopathology*; D010364:Pattern Recognition, Visual; D011601:Psychophysics; D020127:Recovery of Function / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*